Multithreaded Video Converter on Mac?

Is there an app for Mac that can distribute a single video encoding job to several thread to utilize the full potential of the system? I used an application called iFlicks to do video encoding, and as far as I know, it's single-threaded, so even though it can use all my CPU time, it cannot squeeze the best performance out of my system. I am using a 15" MacBook Pro with Retina Display. Also, I knew that there were multithreaded ffmpeg implementation, but I can't figure out how to use that. If anyone could help, it's much appreciated.